Conjugated NiO‐ZnO/GO nanocomposite powder for applications in supercapacitor electrodes material

Abstract

Summary The nanocomposite of NiO‐ZnO/graphene oxide (GO) was synthesized for applications in supercapacitor electrodes material. GO was produced using the modified Hummers' method, and the nanocomposite of NiO‐ZnO/GO was synthesized using the co‐precipitation method. Thin films of nanocomposite powder were deposited on quartzite (glass) and fluorine‐doped tin oxide substrates by a drop casting technique. X‐ray diffraction revealed the crystallographic information of NiO‐ZnO/GO nanocomposites. The surface morphology and elemental composition were studied using a scanning electron microscopy and energy‐dispersive X‐ray spectroscopy, respectively. The electrochemical properties were examined using cyclic voltammetry in a 1.0 M solution of Na2SO4 electrolyte with a three‐electrode system. Moreover, the NiO‐ZnO/GO binary metal oxides nanocomposite based electrodes fabricated for supercapacitor delivered a high specific capacitance of 1690 F g−1 for 1:1/GO sample at a scan rate of 10 mV s−1 and has excellent conductivity due to reduced band gap energy range of 1.52‐1.79 eV and with electrodes resistance of 0.02 Ω. The absence of semicircle in the Nyquist plot denotes low charge transfer resistance of the electrodes. The highest energy densities obtained for 1:1/GO and 2:1/GO are 192 and 148 Wh kg−1, respectively, while the highest power density obtained for 1:1/GO and 2:1/GO are 8.46 and 7.42 W kg−1, respectively. Our study paves way for a facile, affordable, nontoxic, and fast way to synthesis binary transition metal oxides/GO‐based electrodes material for high‐performance supercapacitor.

Performance Evaluation of Graphene Oxide Based Co3O4@GO, MnO2@GO and Co3O4/MnO2@GO Electrodes for Supercapacitors

“…However, band gap can be tuned by combining different constituent transition metal oxides and addition of carbon derivatives, this suits nanocomposite for numerous applications like supercapacitors, photovoltaics, fuel cells, thermoelectric, photo catalysis etc. [30]…”

Evaluation of 8.0 MeV Carbon (C2+) Irradiation Effects on Hydrothermally Synthesized Co3O4−CuO−ZnO@GO Electrodes for Supercapacitor Applications

“…This spectacle behaviour may be credited to recrystallization that took place after receiving energy from the first radiation and increased temperature [2]. Equation 7 and 8 were employed to evaluate the energy (E d ) and power (P d ) densities respectively [36]. …”

“…There is a voltage drop observed in the GCD plots, especially for a current density of 2.0 A/g, this occurs as a result of losses due to resistance offered by the supercapacitor. It normally possesses significant value after numerous charge and discharge cycles sometimes referred to ageing phenomena [36,37]. Results obtained from the cycling test disclose higher cycling stability, with 83.02 % capacitance retention after 5000 cycles.…”

Transformation of GO to rGO due to 8.0 MeV carbon (C++) ions irradiation and characteristics performance on MnO 2 –NiO–ZnO @ GO electrode

“…Similarly, for a current density of 2.0 A/g, specific capacitance obtained are 1945, 1520, 1308, 828 and 315 F/g for pristine, illuminated with 2.25 × 10 15 , 5.0 × 10 15 , 7.5 × 10 15 and 1.0 × 10 16 ions/cm 2 respectively. Equations ) and () were employed to evaluate the energy ( E d ) and power ( P d ) densities, respectively 44 …”